压力分散型锚索和钢管桩在边坡支护中的应用

压力分散型锚索,钢管桩和框架梁的联合支护,在边坡治理中取得了良好的支护效果,为我国在软弱边坡支护方面提供了一种可行的方法。     

复杂地层冲击反循环成孔工艺

在上部为软粘土，下部为涤厚砂砾石的复杂地层中施工，综合采用冲抓十冲击反循环成孔工艺可以取得较好的钻进效率。本文着重介绍了反循环冲击钻进在深厚卵砾石地层中的施工技术。     

Analysis of the effect of traffic exposure on the recovery properties of cut pile carpet using analytical and viscoelastic modeling

Viscoelastic models composing of different combination of spring and dashpot are usually used to explain the mechanical behavior of textile materials. In this work, a viscoelastic model was presented to analyze the effect of traffic exposure on the compression and recovery performance of the pile carpet. Wear test, performed by a Hexapod tumbling machine, was conducted to simulate the traffic exposure. Using a tensile tester, adjusted in compression mode, one cycle of compression–decompression was applied to the samples. The standard nonlinear model was presented to fit the experimental data. Best curve fitting based on the least square method was then used to fit the model to the experimental curve. Different attributions of compression were then analyzed and discussed. The results showed that the standard nonlinear model was fitted to the experimental curves with an acceptable coefficient of regression (R²). The district model parameters, i.e. the spring and dashpot constants, were both decreased as the wear cycles increased. At the higher level of wear cycles, the model parameters showed some increment. The initial compression modulus showed the same trend. This may be explained by the more compactness of the carpet at higher wear cycles. The decompression modulus, compression and the decompression work also decreased with the increase of wear cycles. However, no significant increase of the formers was observed at the higher wear cycles.     

打桩抬高的机理及对策

本文从桩抬高源于打桩挤压产生的土位移出发,分析了桩抬高的机理及其对桩承载力的影响,并根据不同情况提出重打复位或不重打的建议。     

建筑桩基设计中若干问题的探讨

本文对目前建筑桩基设计中的下述问题提出探讨 :a)关于人工挖孔灌注桩与机械成孔灌注桩实际承载能力的比较 ;b)关于桩长与桩端持力层的选择 ;c)关于岩层桩端承载力的确定方法 ;这些问题的解决 ,有利于正确评价桩基的承载能力 ,有利于桩基础设计的优化     

高层建筑筒体下桩筏基础设计方法

针对不同的受力特点，对工程中常用的桩筏基础进行分类，并讨论了目前常用的设计方法。重点探讨了桩筏基础空间桁架理论模型，为进一步研究明确了思路。     

Cavity reverse expansion considering elastoplastic unloading and application in cast-in-situ bored piles

The construction process of a cast-in-situ bored pile is too complicated to be described by the cavity expansion theory with a single process. An exact unified semi-analytical solution for both cylindrical and spherical cavities reverse expansion after unloading in drained soil is developed. The non-associated Mohr-Coulomb model and definition of logarithmic strain are adopted in the reverse plastic zone. This model can be used to solve the stress and displacement fields of the soil around a bored pile along both the horizontal and depth directions. Parametric analysis shows that the effect of the unloading phase does not change the ultimate pressure of cavity reverse expansion compared with in situ expansion. The cavity cannot re-expand to its initial radius even though the cavity pressure reloads to the initial value. The increase of internal friction angle, cohesion, and Young's modulus has a positive effect on radius recovery, while the dilatancy angle has a negative effect. A simulation of the construction process of cast-in-situ bored piles is presented, where the role of boring, mud wall protection, and concrete placement is defined. An example that describes the stress and displacement fields around a pile shows that the total radial displacement of soil around the pile is dominated by contraction displacement. And it is closely related to depth and horizontal distance. The results of both parameter analysis and example analysis demonstrate that a low reverse cavity pressure corresponds to a stress-reduction area surrounding the cavity.     

静压微型预制桩的单桩竖向承载力分析研究

为了在工程中合理应用静压微型预制桩 ,进行合理安全条件下的设计 ,以确保建筑物的安全可靠与其造价经济合理 ,我们对JGJ 94 94规范有关预制桩部分的编制说明及编制依据等资料进行了学习总结与分析 ,在此基础上结合我们的试验研究与工程实践对静压微型预制桩单桩竖向承载力的问题进行了初步分析。     

大体积混凝土承台温控分析

以中博会展中心大体积承台的施工为例,探讨了大体积混凝土施工的温度控制措施;按平面应变理论建立了数值分析模型,利用有限元对大体积承台进行了温度场和应力场的模拟分析;对承台内部的混凝土温度进行了测量,并对实测结果进行了分析。     

基桩检测远程监控规范管理探讨

工程检测领域应用信息化管理已成为一个重要的监管手段,本文试从福建省运用自动采集远程监控系统进行全省基桩静载检测试验监管中遇到的若干问题进行研究,分析影响因素,从技术、制度、管理等方面提出规范基桩检测行为的措施,确保基桩检测数据的真实性和有效性。